[Dwarf] Reference the correct CU when inlining

Sometimes when a function is inlined into a different CU, `llvm-dwarfdump --verify` would find an inlined subroutine with an invalid abstract origin. This is because `DwarfUnit::addDIEEntry()` will incorrectly assume the inlined subroutine and the abstract origin are from the same CU if it can't find the CU for the inlined subroutine.

In the added test, the inlined subroutine for `bar()` is created before the CU for `B.swift` is created, so it tries to point to `goo()` in the wrong CU. Interestingly, if we swap the order of the two functions then we don't see a crash since the module for `goo()` is created first.

The fix is to give a parent DIE to `ScopeDIE` before calling `addDIEEntry()` so that its CU can be found. Luckily, `constructInlinedScopeDIE()` is only called once so we can pass it the DIE of the scope's parent and give it a child just after it's created.

`constructInlinedScopeDIE()` should always return a DIE, so assert that it is not null.

Reviewed By: aprantl

Differential Revision: https://reviews.llvm.org/D135114

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index b26960c..81e688e 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -547,11 +547,8 @@ void DwarfCompileUnit::constructScopeDIE(LexicalScope *Scope,
 
   // Emit inlined subprograms.
   if (Scope->getParent() && isa<DISubprogram>(DS)) {
-    DIE *ScopeDIE = constructInlinedScopeDIE(Scope);
-    if (!ScopeDIE)
-      return;
-
-    ParentScopeDIE.addChild(ScopeDIE);
+    DIE *ScopeDIE = constructInlinedScopeDIE(Scope, ParentScopeDIE);
+    assert(ScopeDIE && "Scope DIE should not be null.");
     createAndAddScopeChildren(Scope, *ScopeDIE);
     return;
   }
@@ -650,9 +647,8 @@ void DwarfCompileUnit::attachRangesOrLowHighPC(
   attachRangesOrLowHighPC(Die, std::move(List));
 }
 
-// This scope represents inlined body of a function. Construct DIE to
-// represent this concrete inlined copy of the function.
-DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
+DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope,
+                                                DIE &ParentScopeDIE) {
   assert(Scope->getScopeNode());
   auto *DS = Scope->getScopeNode();
   auto *InlinedSP = getDISubprogram(DS);
@@ -662,6 +658,7 @@ DIE *DwarfCompileUnit::constructInlinedScopeDIE(LexicalScope *Scope) {
   assert(OriginDIE && "Unable to find original DIE for an inlined subprogram.");
 
   auto ScopeDIE = DIE::get(DIEValueAllocator, dwarf::DW_TAG_inlined_subroutine);
+  ParentScopeDIE.addChild(ScopeDIE);
   addDIEEntry(*ScopeDIE, dwarf::DW_AT_abstract_origin, *OriginDIE);
 
   attachRangesOrLowHighPC(*ScopeDIE, Scope->getRanges());

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index 61412cd..7a1bea4 100644 (file)
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -204,9 +204,9 @@ public:
   void attachRangesOrLowHighPC(DIE &D,
                                const SmallVectorImpl<InsnRange> &Ranges);
 
-  /// This scope represents inlined body of a function. Construct
+  /// This scope represents an inlined body of a function. Construct a
   /// DIE to represent this concrete inlined copy of the function.
-  DIE *constructInlinedScopeDIE(LexicalScope *Scope);
+  DIE *constructInlinedScopeDIE(LexicalScope *Scope, DIE &ParentScopeDIE);
 
   /// Construct new DW_TAG_lexical_block for this scope and
   /// attach DW_AT_low_pc/DW_AT_high_pc labels.

diff --git a/llvm/test/DebugInfo/Generic/cross-cu-inlining-2.ll b/llvm/test/DebugInfo/Generic/cross-cu-inlining-2.ll
new file mode 100644 (file)
index 0000000..dba084d
--- /dev/null
+++ b/llvm/test/DebugInfo/Generic/cross-cu-inlining-2.ll
@@ -0,0 +1,83 @@
+; REQUIRES: object-emission
+; RUN: %llc_dwarf %s -O0 -filetype=obj -o %t.o
+; RUN: llvm-dwarfdump %t.o --debug-info --verbose | FileCheck %s --implicit-check-not "{{DW_TAG|NULL}}"
+; RUN: llvm-dwarfdump %t.o --debug-info --verify
+
+; Test that we can inline from a different CU in a way that has triggered a bug.
+
+define void @foo() !dbg !24 {
+  ret void, !dbg !28
+}
+
+define void @bar() !dbg !34 {
+  ret void, !dbg !35
+}
+
+!llvm.dbg.cu = !{!0, !3}
+!llvm.module.flags = !{!5, !6, !7, !8, !9, !10, !11, !12, !13, !14, !15, !16, !17, !18, !19, !20, !21, !22, !23}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !1, isOptimized: true, runtimeVersion: 5, emissionKind: FullDebug, globals: !2, imports: !2)
+!1 = !DIFile(filename: "A.swift", directory: "")
+!2 = !{}
+!3 = distinct !DICompileUnit(language: DW_LANG_Swift, file: !4, isOptimized: true, runtimeVersion: 5, emissionKind: FullDebug, imports: !2)
+!4 = !DIFile(filename: "B.swift", directory: "")
+!5 = !{i32 2, !"SDK Version", [2 x i32] [i32 16, i32 0]}
+!6 = !{i32 1, !"Objective-C Version", i32 2}
+!7 = !{i32 1, !"Objective-C Image Info Version", i32 0}
+!8 = !{i32 1, !"Objective-C Garbage Collection", i8 0}
+!9 = !{i32 1, !"Objective-C Class Properties", i32 64}
+!10 = !{i32 7, !"Dwarf Version", i32 4}
+!11 = !{i32 2, !"Debug Info Version", i32 3}
+!12 = !{i32 1, !"wchar_size", i32 4}
+!13 = !{i32 8, !"branch-target-enforcement", i32 0}
+!14 = !{i32 8, !"sign-return-address", i32 0}
+!15 = !{i32 8, !"sign-return-address-all", i32 0}
+!16 = !{i32 8, !"sign-return-address-with-bkey", i32 0}
+!17 = !{i32 8, !"PIC Level", i32 2}
+!18 = !{i32 7, !"uwtable", i32 1}
+!19 = !{i32 7, !"frame-pointer", i32 1}
+!20 = !{i32 1, !"Swift Version", i32 7}
+!21 = !{i32 1, !"Swift ABI Version", i32 7}
+!22 = !{i32 1, !"Swift Major Version", i8 5}
+!23 = !{i32 1, !"Swift Minor Version", i8 7}
+!24 = distinct !DISubprogram(name: "foo", scope: !25, file: !1, line: 116, type: !27, scopeLine: 116, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!25 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "FooTy", scope: !26, file: !1, size: 64, elements: !2)
+!26 = !DIModule(scope: null, name: "Mod")
+!27 = !DISubroutineType(types: !2)
+!28 = !DILocation(line: 0, scope: !29, inlinedAt: !32)
+!29 = distinct !DISubprogram(name: "init", scope: !31, file: !30, type: !27, spFlags: DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!30 = !DIFile(filename: "<compiler-generated>", directory: "")
+!31 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "ModController", scope: !26, file: !4, size: 64, elements: !2, runtimeLang: DW_LANG_Swift)
+!32 = !DILocation(line: 117, column: 29, scope: !33)
+!33 = distinct !DILexicalBlock(scope: !24, file: !1, line: 116, column: 68)
+!34 = distinct !DISubprogram(name: "bar", scope: !31, file: !4, line: 21, type: !27, scopeLine: 21, unit: !3, retainedNodes: !2)
+!35 = !DILocation(line: 0, scope: !36, inlinedAt: !37)
+!36 = distinct !DISubprogram(name: "goo", scope: !26, file: !30, type: !27, unit: !3, retainedNodes: !2)
+!37 = !DILocation(line: 21, column: 26, scope: !34)
+
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_module
+; CHECK:     DW_TAG_structure_type
+; CHECK: [[INIT:0x.*]]: DW_TAG_subprogram
+; CHECK;         DW_AT_name [DW_FORM_strp]  ({{.*}} = "init")
+; CHECK:       DW_TAG_subprogram
+; CHECK;         DW_AT_name [DW_FORM_strp]  ({{.*}} = "bar")
+; CHECK:         DW_TAG_inlined_subroutine
+; CHECK:           DW_AT_abstract_origin [DW_FORM_ref_addr] (0x00000000[[GOO:.*]] "goo")
+; CHECK:         NULL
+; CHECK:       NULL
+; CHECK:     DW_TAG_structure_type
+; CHECK:       DW_TAG_subprogram
+; CHECK;         DW_AT_name [DW_FORM_strp]  ({{.*}} = "foo")
+; CHECK:         DW_TAG_inlined_subroutine
+; CHECK:           DW_AT_abstract_origin [DW_FORM_ref4]  ({{.*}} => {[[INIT]]} "init")
+; CHECK:         NULL
+; CHECK:       NULL
+; CHECK:     NULL
+; CHECK:   NULL
+; CHECK: DW_TAG_compile_unit
+; CHECK:   DW_TAG_module
+; CHECK: 0x[[GOO]]: DW_TAG_subprogram
+; CHECK;       DW_AT_name [DW_FORM_strp]  ({{.*}} = "goo")
+; CHECK:     NULL
+; CHECK:   NULL